Excel 2007 : Split data from a single column to plot a two-line chart

I'm STUCK!

This is the first time I've tried charts in xl 2007, and I'm not getting it easily.

The chart needs:

1. A Y-axis of dates (in mm/dd/yyy) format (There are duplicate dates in this list as well as large gaps)
2. An X-axis with a scale from 0 to 100%

Here's the trouble.

Column A represents the employees' hire date.
Column B represents their percentage in the whole list of people (guy hired first is 0%, last guy is 100%..you get the idea).
Column C has a mark beside the employees that came from a different company but are now part of the whole list.

I WANT TO: be able to go down all the different dates of hire (in chronological ascending order) in the Y-axis and look across to see their percentage (percentage of position in the whole group). This would require the top date to be the oldest and the bottom date to be the newest.

HOWEVER: I want one line to represent each group--that way a person from group #1 can find their date of hire and look across to see their position on the totum pole quickly.


Here is a sample of the excel table and an idea I drew of what I'm after: